Help!!!!

Samuel invested $7,800 in an account paying an interest rate of 5 1/2 % compounded continuously. Claire invested $7,800 in an account paying an interest rate of 5 5/8% compounded daily. To the nearest hundredth of a year, how much longer would it take for Samuel's money to double than for Claire's money to double?

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Answer:

0.28 yr  

Step-by-step explanation:

To find the doubling time with continuous compounding, we should look at the formula:

[tex]FV = PVe^{rt}[/tex]

FV = future value, and

PV = present value

If FV is twice the PV, we can calculate the doubling time, t

[tex]\begin{array}{rcl}2 & = & e^{rt}\\\ln 2 & = & rt\\t & = & \dfrac{\ln 2}{r} \\\end{array}[/tex]

1. Samuel's doubling time

[tex]\begin{array}{rcl}t & = & \dfrac{\ln 2}{0.055}\\\\& = & \textbf{12.603 yr}\\\end{array}[/tex]

2. Claire's doubling time

[tex]\begin{array}{rcl}t & = & \dfrac{\ln 2}{0.05625}\\\\& = & \textbf{12.323 yr}\\\end{array}[/tex]

3. Samuel's doubling time vs Claire's

12.603 - 12.323 = 0.28 yr

It would take 0.28 yr longer for Samuel's money to double than Claire's.